Conventionally, a technique for mounting an electronic component, such as a connecter, on an electronic circuit board, is well known, in which a holding member attached to an electronic component is pressed into a through hole formed in an electronic circuit board, with the holding member securing the electronic component on the electronic circuit board. Furthermore, in order to firmly fix an electronic component to an electronic circuit board, the holding member may be soldered to the electronic circuit board.
Japanese Utility Model Application Publication No. H6-62486 and U.S. Pat. No. 5,529,514 disclose such a holding member, where the holding member is elastically deformed in a plane direction and formed by stamping a metal plate, so as to press the holding member into a through hole of an electronic circuit board. The holding member has a shape in which a latch is provided on each of the outer sides respectively of a pair of legs extending in a bifurcated manner from a head part fixed to a connector. When the legs of the holding member are plunged into the through hole of the electronic circuit board, the latch thereof penetrate the through hole of the electronic circuit board and hook on the electronic circuit board. Accordingly, even in a state where the holding member fixed to the connecter is simply plunged into the through hole and is not yet soldered thereto, the connector can be held by the holding member so as not to be detached from the electronic circuit board. However, the holding member is planar, and the pair of legs are configured to be elastically deformed only in a plane direction. Accordingly, compared to a spring which is to be elastically deformable in a board thickness direction, a larger force to cause elastic deformation is required, and it is difficult to reduce a spring constant. In addition, an amount of elastic deformation is small, and a range up to plastic deformation is small. Accordingly, cut surfaces of the pair of legs obtained by stamping a metal plate are to forcibly come into contact with an inner surface of the through hole when the legs are plunged thereinto. Therefore, the inner surface of the through hole may be damaged.
As a holding member to deal with such a problem, for example, proposed is a holding member which has a pair of legs extending from a plate-like base fixed to a connector in a substantially same direction, respectively having broad spring pieces being elastically deformable in a board thickness direction, and facing with each other (for example, refer to Japanese Patent Application Publication No. 2007-128772). When the holding member is plunged into a through hole, the pair of legs are elastically deformed in a board thickness direction. Then, the holding member is held such that a pair of legs comes into plane contact with an inner surface of the through hole so that the holding member is not detached from an electronic circuit board, in a state where the holding member is simply plunged into the through hole and is not soldered. Furthermore, according to the holding member, each of the outer surfaces respectively of a pair of legs gently comes into plane contact with the inner surface of the through hole when the holding member is pressed into the through hole, so that damage on the inner surface of the through hole can be prevented. However, the holding member has a disadvantage in that it is difficult to increase elasticity (spring constant) of the legs. Accordingly, the holding force of the holding member, in the state of being simply plunged into the through hole and not yet soldered thereto, is small. Therefore when, for example, the holding member is handled and moved by a robot in this state, or, when the holding member is strongly pulled in this state, the legs of the holding member may be easily pulled out from the through hole.